arm64/fpsimd: Remove warning for SME without SVE

Support for SME without SVE is architecturally valid and has now been tested
well enough so let's remove the warning message that is displayed at boot.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230209-arm64-sme-no-sve-v1-1-74eb3df2f878@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>